u joints..

[jasonroman]

how can i tell if they are going bad or are bad?
when i drive down the road at a steady speed. i feel like the truck almost skips a beat. kinda hard to explain. i stay going down the road at speed but almost like i feel the truck stop and go. not like i am on brakes but almost like i feel either the drive shaft spin or the wheels turning..

[scotts62]

Sounds more like a miss fire... In park go from reverse to drive and you will hear the "click" of a ujoint or lay under and push on drive line and try and move to see if there is any give or slack.

[jasonroman]

Thanks for reply. Miss fire? Where and how ? Just tuned up. Don't think it's misfire. Can it be something with rear end? Wheels are str8 and tires are new. Thought maybe it was tires but they are new. Wish I could explain better

[sntrym95]

What year is your truck? Please give more specifics about it. It sounds exactly like a misfire. A bad ujoint will cause a consistent vibration at certain speeds. May also squeal under load, like acceleration.

[jasonroman]

1994
i hear a sqeal noise only when i brake. coming to a complete stop make noise from rear of truck. i think it has to do with rear brakes. but i just had all brakes done. all new parts front and rear.

misfire = ??

[brad_man_72]

If your driveshaft is "spinning" it is in multiple pieces on the highway. Or the slip and stub are very worn and should be causing a massive vibration.

Did you have this problem before your tune up?
Make sure your cap and plug wires are tight.
Did you check the gap on all of your plugs?

[jasonroman]

--------------------------------------------------------------------------------

If your driveshaft is "spinning" it is in multiple pieces on the highway. Or the slip and stub are very worn and should be causing a massive vibration

not really sure what you mean by this.??
i did have the issue before tune up. thought it was tires. i did gap plugs before putting them in. ill douple check that everything is tight.
i asked my kid if he felt what i was feeling or if it was in my head. but he says he feels the same thing. almost like a pause in rotation or sometihng. but no pause.
kinda like if while im driving say at 40mph someone is behind the truck pulling back on it every turn of tire.
i know i am not doing a good job explaining this. just not sure how to word what i feel.

[sntrym95]

Ok, try this: Get on a road where no one else is, if possible. Get the truck to 40 mph or wherever you feel the vibration. Throw it into neutral and coast. Do you still feel it? Also, you can turn the truck completely off in neutral to see, but I only recommend this if you know what you are doing.

[68c10owner]

Originally Posted by sntrym95

Ok, try this: Get on a road where no one else is, if possible. Get the truck to 40 mph or wherever you feel the vibration. Throw it into neutral and coast. Do you still feel it? Also, you can turn the truck completely off in neutral to see, but I only recommend this if you know what you are doing.

And make sure you dont lock the steering wheel.

[sntrym95]

It won't (shouldn't) lock unless it's in park.

[buddy_1]

You could pull the driveshaft out and work the joints by hand. First one way then the other feeling for binding or tight spots. Look at the rubber seals around the caps for signs of rust or black lines where it looks like its starting to leak grease out. If you've got a bad one you should be able to feel it. Buddy

[Cape Codder]

Originally Posted by buddy_1

You could pull the driveshaft out and work the joints by hand. First one way then the other feeling for binding or tight spots. Look at the rubber seals around the caps for signs of rust or black lines where it looks like its starting to leak grease out. If you've got a bad one you should be able to feel it. Buddy

Best answer so far

[jasonroman]

thanks for replies. i may try and pull it out this weekend. may go ahead and buy the u joints that way if i am able to get them shaft out i figure i may as well change when there. now gotta look for some info on how to.. i am not a mechanic.
thanks again for replies and help

[400sbctruck]

Given the fresh tune up, could it be fuel delivery/pump problems?
Shake the driveshaft at the joint, any slack at all and its bad. Fwiw precision makes the best most durable ones in the aftermarket. Should be a #354.

[Mr_Rich]

Bad U-joints: picture #1. This is an example of a U-joint that was over twenty years old. I didn't think it was this bad, but it literally fell apart when I pulled the driveshaft along with all the other work I did on my truck this past summer. It went together real nice in picture #2. Typically bad U-joints will cause vibration and clunk noises in the driveline.

[Mr_Rich]

A large C-clamp and a press like this are helpful tools to have...

[Cape Codder]

If you don't have a vise that opens wide you can rent a ball joint press from the parts store . They work fine.

[jasonroman]

thanks for replies and pics. might try this this weekend